Variability in forest floor at different spatial scales in a natural forest in the Carpathians: effect of windthrows and mesorelief

2008 ◽  
Vol 38 (10) ◽  
pp. 2596-2606 ◽  
Author(s):  
P. Šamonil ◽  
K. Král ◽  
J. Douda ◽  
B. Šebková
Keyword(s):  
Spatial Variability ◽  
Spatial Dependence ◽  
Forest Floor ◽  
Spatial Scales ◽  
Beech Forest ◽  
High Variability ◽  
Organic Horizon ◽  
Fine Scale ◽  
Coarse Scale ◽  
Organic Horizons

Spatial variability of humus properties in a natural fir–beech forest was studied along with the influence of windthrows and mesorelief on this variability. In 1720 windthrows the thickness and form of the organic horizons were studied in three positions — mound, pit, and undisturbed control. On undisturbed sites, substantial variability of thickness and forms of the organic horizons was found on a fine scale (0–10 m). Close spatial dependence of some humus characteristics was found on a coarser scale (20–120 m). The mesorelief was found to be one of the key autocorrelation factors. The level of spatial dependence was not uniform; it differed between the fermented and humification horizons and among their forms. The presence of windthrows increased the variability of humus thickness on both fine (0–10 m) and coarse (level of entire locality, i.e., 11 ha) scales. However, windthrows did not increase the variability of organic horizon forms (OHFs) on a fine scale. High variability of OHFs is probably a property of fully developed mature humus in a natural fir–beech forest. On a coarse scale, the presence of pits increased the frequency of fermented zoogenous and humification residual horizons on the study area.

Assessing Clark's nutcracker seed-caching flights using maternally inherited mitochondrial DNA of whitebark pine

2002 ◽  
Vol 32 (6) ◽  
pp. 1103-1107 ◽  
Author(s):  
Bryce A Richardson ◽  
Ned B Klopfenstein ◽  
Steven J Brunsfeld
Keyword(s):  
Mitochondrial Dna ◽  
Spatial Scales ◽  
Random Pattern ◽  
Fine Scale ◽  
Whitebark Pine ◽  
Coarse Scale ◽  
Nucifraga Columbiana ◽  
Seed Caching ◽  
Clark's Nutcracker ◽  
Haplotype Frequencies

Maternally inherited mitochondrial DNA haplotypes in whitebark pine (Pinus albicaulis Engelm.) were used to examine the maternal genetic structure at three hierarchical spatial scales: fine scale, coarse scale, and inter population. These data were used to draw inferences into Clark's nutcracker (Nucifraga columbiana Wilson) seed-caching flight distances. Statistical analyses of fine-scale and coarse-scale distribution of haplotypes showed no apparent signs of deviation from a random pattern. This suggests nutcrackers are effective in dispersal of seed within populations, which is consistent with data gathered on nutcracker seed-caching behavior. However, the lack of homogeneity in haplotype frequencies among populations indicates nutcrackers rarely disperse seeds across large gaps (>20 km) in subalpine habitat.

Abundance, spatial distribution and habitat relationships of echinoderms in the Cabo Verde Archipelago (eastern Atlantic)

2008 ◽  
Vol 59 (6) ◽  
pp. 477 ◽  
Author(s):  
Laura Entrambasaguas ◽  
Ángel Pérez-Ruzafa ◽  
Jose A. García-Charton ◽  
Ben Stobart ◽  
Juan José Bacallado
Keyword(s):  
Spatial Variability ◽  
Habitat Structure ◽  
Sea Urchins ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Fine Scale ◽  
Cabo Verde ◽  
Heterogeneous Habitats ◽  
Species Abundances ◽  
Species Specific

The analysis of spatial variability in distribution and abundance of echinoderms may help in identifying the range of processes that can explain the observed patterns of this important component of benthic communities. The distribution and abundance of the echinoderm assemblage inhabiting the shallow rocky reefs at the Cabo Verde archipelago (where few studies other than descriptive ones have been performed until now) was quantified at three spatial scales (among islands, between locations within islands, and among replicates), at two depth strata, and related to fine-scale variation of habitat structure. Total echinoderm abundance and the abundance of the sea urchins Diadema antillarum and Eucidaris tribuloides, and the holothurian Euapta lappa were heterogeneous at the largest considered scale. Most species and habitat descriptors exhibited spatial variability at finer scales. There were significant relationships between habitat architecture and depth and both assemblage parameters and species abundances. Although the effects of habitat structure were species-specific, the probability of occurrence of Asteroidea, Ophiuroidea and Holothuroidea species was higher in heterogeneous habitats. Meanwhile Echinoidea and Holothuroidea species showed higher correlations to complex habitats. The observed spatial patterns are inferred to reflect behavioural responses to fine-scale microhabitat complexity, as well as broad-scale oceanic variables and recruitment dynamics.

scholarly journals Hybrid motion illusions as examples of perceptual conflict

2021 ◽  
Vol 2 ◽  
Author(s):  
Arthur Shapiro
Keyword(s):  
Spatial Frequency ◽  
Spatial Scales ◽  
High Spatial Frequency ◽  
Natural World ◽  
Fine Scale ◽  
Frequency Content ◽  
Coarse Scale ◽  
Trade Offs ◽  
Spatial Frequencies ◽  
Contrast Information

Shapiro and Hedjar (2019) proposed a shift in the definition of illusion, from ‘differences between perception and reality’ to ‘conflicts between possible constructions of reality’. This paper builds on this idea by presenting a series of motion hybrid images that juxtapose fine scale contrast (high spatial frequency content) with coarse scale contrast-generated motion (low spatial frequency content). As is the case for static hybrid images, under normal viewing conditions the fine scale contrast determines the perception of motion hybrid images; however, if the motion hybrid image is blurred or viewed from a distance, the perception is determined by the coarse scale contrast. The fine scale contrast therefore masks the perception of motion (and sometimes depth) produced by the coarser scale contrast. Since the unblurred movies contain both fine and coarse scale contrast information, but the blurred movies contain only coarse scale contrast information, cells in the brain that respond to low spatial frequencies should respond equally to both blurred and unblurred movies. Since people undoubtedly differ in the optics of their eyes and most likely in the neural processes that resolve conflict across scales, the paper suggests that motion hybrid images illustrate trade-offs between spatial scales that are important for understanding individual differences in perceptions of the natural world.

scholarly journals Spatial variability of the horizontal structure and production of biomass in Massai grass in an agropastoral system

2021 ◽  
Vol 16 (3) ◽  
pp. 238-244
Author(s):  
Carlos Henrique Batista ◽  
Otacílio Silveira Júnior ◽  
Ítalo Cordeiro Silva Lima ◽  
José Alberto Ferreira Cardoso ◽  
Rossini Sôffa da Cruz ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Spatial Dependence ◽  
Structural Characteristics ◽  
Management Plan ◽  
High Variability ◽  
Geostatistical Analysis ◽  
Descriptive Statistics ◽  
Horizontal Structure ◽  
Degraded Pasture ◽  
Recovery Management

In Brazil, 60% to 80% of cultivated pastures show some degradation level. Thus, the objective was to evaluate the variability of the horizontal structure and biomass of Massai grass in an agropastoral system as a diagnosis of degraded pasture. We performed the georeferencing in a 12m × 13m mesh, totaling 48 sampling stations, and evaluated grass's biomass and structural characteristics at each station. We submitted the data to descriptive statistics and geostatistical analysis. We observed a process of degradation of pasture in the experimental area. Under these conditions, most of the characteristics of the pasture's horizontal structure and the production of biomass showed spatial dependence with high variability. Geostatistics efficiently represented and understood the variability of the studied attributes, enabling developing a specific pasture recovery management plan.

scholarly journals Repeated surveying over 6 years reveals that fine-scale habitat variables are key to tropical mountain ant assemblage composition and functional diversity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mulalo M. Muluvhahothe ◽  
Grant S. Joseph ◽  
Colleen L. Seymour ◽  
Thinandavha C. Munyai ◽  
Stefan H. Foord
Keyword(s):  
Climate Change ◽  
Species Composition ◽  
High Altitude ◽  
Functional Diversity ◽  
Large Scale ◽  
Climate Models ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Composition Analysis ◽  
Fine Scale

AbstractHigh-altitude-adapted ectotherms can escape competition from dominant species by tolerating low temperatures at cooler elevations, but climate change is eroding such advantages. Studies evaluating broad-scale impacts of global change for high-altitude organisms often overlook the mitigating role of biotic factors. Yet, at fine spatial-scales, vegetation-associated microclimates provide refuges from climatic extremes. Using one of the largest standardised data sets collected to date, we tested how ant species composition and functional diversity (i.e., the range and value of species traits found within assemblages) respond to large-scale abiotic factors (altitude, aspect), and fine-scale factors (vegetation, soil structure) along an elevational gradient in tropical Africa. Altitude emerged as the principal factor explaining species composition. Analysis of nestedness and turnover components of beta diversity indicated that ant assemblages are specific to each elevation, so species are not filtered out but replaced with new species as elevation increases. Similarity of assemblages over time (assessed using beta decay) did not change significantly at low and mid elevations but declined at the highest elevations. Assemblages also differed between northern and southern mountain aspects, although at highest elevations, composition was restricted to a set of species found on both aspects. Functional diversity was not explained by large scale variables like elevation, but by factors associated with elevation that operate at fine scales (i.e., temperature and habitat structure). Our findings highlight the significance of fine-scale variables in predicting organisms’ responses to changing temperature, offering management possibilities that might dilute climate change impacts, and caution when predicting assemblage responses using climate models, alone.

scholarly journals Spatial Downscaling of TRMM Precipitation Using Geostatistics and Fine Scale Environmental Variables

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
No-Wook Park
Keyword(s):  
Environmental Variables ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Tropical Rainfall Measuring Mission ◽  
Predictive Performance ◽  
Environmental Modeling ◽  
Fine Scale ◽  
Coarse Scale ◽  
Uncertainty Measures ◽  
Trmm Precipitation

A geostatistical downscaling scheme is presented and can generate fine scale precipitation information from coarse scale Tropical Rainfall Measuring Mission (TRMM) data by incorporating auxiliary fine scale environmental variables. Within the geostatistical framework, the TRMM precipitation data are first decomposed into trend and residual components. Quantitative relationships between coarse scale TRMM data and environmental variables are then estimated via regression analysis and used to derive trend components at a fine scale. Next, the residual components, which are the differences between the trend components and the original TRMM data, are then downscaled at a target fine scale via area-to-point kriging. The trend and residual components are finally added to generate fine scale precipitation estimates. Stochastic simulation is also applied to the residual components in order to generate multiple alternative realizations and to compute uncertainty measures. From an experiment using a digital elevation model (DEM) and normalized difference vegetation index (NDVI), the geostatistical downscaling scheme generated the downscaling results that reflected detailed characteristics with better predictive performance, when compared with downscaling without the environmental variables. Multiple realizations and uncertainty measures from simulation also provided useful information for interpretations and further environmental modeling.

scholarly journals Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales

2014 ◽  
Vol 369 (1643) ◽  
pp. 20130194 ◽  
Author(s):  
Michael D. Madritch ◽  
Clayton C. Kingdon ◽  
Aditya Singh ◽  
Karen E. Mock ◽  
Richard L. Lindroth ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Populus Tremuloides ◽  
Spatial Scales ◽  
Imaging Spectroscopy ◽  
Spectral Signature ◽  
Spectral Variation ◽  
Fine Scale ◽  
Below Ground ◽  
Landscape Scales ◽  
Spectrometer Data

Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

scholarly journals Spatial variability and mapping of soil fertility status in a high-potential smallholder farming area under sub-humid conditions in Zimbabwe

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Gabriel Soropa ◽  
Olton M. Mbisva ◽  
Justice Nyamangara ◽  
Ermson Z. Nyakatawa ◽  
Newton Nyapwere ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Soil Ph ◽  
Strong Evidence ◽  
Spatial Dependence ◽  
Random Component ◽  
Smallholder Farming ◽  
Mineral N ◽  
Spatial Trend ◽  
Spatial Trends

AbstractA study was conducted to examine spatial variability of soil properties related to fertility in maize fields across varying soil types in ward 10 of Hurungwe district, Zimbabwe; a smallholder farming area with sub-humid conditions and high yield potential. Purposively collected and geo-referenced soil samples were analyzed for texture, pH, soil organic carbon (OC), mineral N, bicarbonate P, and exchangeable K. Linear mixed model was used to analyze spatial variation of the data. The model allowed prediction of soil properties at unsampled sites by the empirical best linear unbiased predictor (EBLUP). Evidence for spatial dependence in the random component of the model was evaluated by calculating Akaike’s information criterion. Soil pH ranged from 4.0 to 6.9 and showed a strong spatial trend increasing from north to south, strong evidence for a difference between the home and outfields with homefields significantly higher and between soil textural classes with the sand clay loam fraction generally higher. Soil OC ranged from 0.2 to 2.02% and showed no spatial trend, but there was strong evidence for a difference between home and outfields, with mean soil OC in homefields significantly larger, and between soil textural classes, with soil OC largest in the sandy clay loams. Both soil pH and OC showed evidence for spatial dependence in the random effect, providing a basis for spatial prediction by the EBLUP, which was presented as a map. There were significant spatial trends in mineral N, available P and exchangeable K, all increasing from north to south; significant differences between homefields and outfields (larger concentrations in homefields), and differences between the soil textural classes with larger concentrations in the sandy clay loams. However, there was no evidence for spatial dependence in the random component, so no attempt was made to map these variables. These results show how management (home fields vs outfields), basic soil properties (texture) and other factors emerging as spatial trends influence key soil properties that determine soil fertility in these conditions. This implies that the best management practices may vary spatially, and that site-specific management is a desirable goal in conditions such as those which apply in Ward 10 of Hurungwe district in Zimbabwe.

Effect of Savanna windrow wood burning on the spatial variability of soil properties

2021 ◽  
Vol 51 ◽  
Author(s):  
Diogo Neia Eberhardt ◽  
Robélio Leandro Marchão ◽  
Pedro Rodolfo Siqueira Vendrame ◽  
Marc Corbeels ◽  
Osvaldo Guedes Filho ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spatial Variability ◽  
Spatial Dependence ◽  
Chemical Properties ◽  
Spatial Arrangement ◽  
Nugget Effect ◽  
Tropical Savannas ◽  
Geostatistical Methods ◽  
Exchangeable Ca ◽  
Spherical Models

ABSTRACT Tropical Savannas cover an area of approximately 1.9 billion hectares around the word and are subject to regular fires every 1 to 4 years. This study aimed to evaluate the influence of burning windrow wood from Cerrado (Brazilian Savanna) deforestation on the spatial variability of soil chemical properties, in the field. The data were analysed by using geostatistical methods. The semivariograms for pH(H2O), pH(CaCl2), Ca, Mg and K were calculated according to spherical models, whereas the phosphorus showed a nugget effect. The cross semi-variograms showed correlations between pH(H2O) and pH(CaCl2) with other variables with spatial dependence (exchangeable Ca and Mg and available K). The spatial variability maps for the pH(H2O), pH(CaCl2), Ca, Mg and K concentrations also showed similar patterns of spatial variability, indicating that burning the vegetation after deforestation caused a well-defined spatial arrangement. Even after 20 years of use with agriculture, the spatial distribution of pH(H2O), pH(CaCl2), Ca, Mg and available K was affected by the wood windrow burning that took place during the initial deforestation.

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